This invention relates to self-inflating devices and to valves which allow air to enter or escape from enclosures such as self-inflating devices.
Self-inflating cushions have many uses including lumbar support, neck support, hip protection, seat cushions and the like. For the sake of convenience, the invention will be described in relation to a self-inflating cushion for supporting a body part but the invention is not limited thereto.
Many people suffer from back or neck pain and require some form of support to help alleviate the discomfort they endure. Present day lifestyles can result in weak or underdeveloped back muscles. Many people sit in uncomfortable or poorly designed seating which accentuates or exacerbates the problem. For example, sitting for long periods in an office or other work place, travelling in automobiles or on aircraft, or even sitting on a chair watching television, can result in an individual suffering discomfort from back pain if, for example, the seating is poorly designed, or if the individual does not practise correct posture positions, or if the individual already has some anatomical deterioration of the spine.
Discomfort from spinal pain can often be avoided or reduced by the use of cushions or other lumbar support means. However, the problem with most support cushions is that they are often of a shape which provides inadequate or improper support of the spine and/or they are of a shape which makes them inconvenient or difficult to carry or to store.
Inflatable back, head and neck support cushions are known, but these tend to rely entirely on air pressure or on a soft or expandable substance, such as wool or foam, respectively, for their shape and support. In many cases this means that use and adjustment is inadequate or inconvenient.
Known self-inflating cushions suffer from a number of disadvantages arising from the operation of the valve which allows air to enter or escape from the cushion. This is the case in respect of the self-inflating cushion disclosed in International Patent Application PCT/AU96/00761. The object of this invention is to provide an improved self-inflating cushion and an improved valve for such cushions and other enclosures.
According to one aspect of the invention there is provided a self-inflating device comprising an envelope defining a closed space, a compressible material contained within the envelope and valve means adapted to allow air into the envelope so that the compressed material can expand to enlarge the support device and to allow air out of the envelope so that the material may be compressed and the support device reduced in size, said valve means comprising a valve member and a valve seat adapted to form a seal therebetween when the valve is closed, an actuator which whilst actuated separates the valve member and valve seat to permit air flow into and out of the device for adjustment of the volume of air within the device and locking means for maintaining the valve fully open when it is desired to fill or empty the device with air.
According to another aspect of the invention there is provided a valve for controlling the flow of air into and out of an enclosure such as a self-inflating cushion comprising a valve member and a valve seat adapted to form a seal therebetween when the valve is closed, an actuator which whilst actuated separates the valve member and valve seat to permit air to flow into and out of the enclosure for adjustment of the volume of air within the enclosure and locking means for maintaining the valve fully open when it is desired to fill or empty the enclosure with air.
In one form of the invention, the actuator is connected to the valve member and spring biased so as to retain the valve member and valve seat in their closed position. The actuator is arranged so that upon an initial movement it separates the valve member and valve seat to allow adjustment of the volume of air in the enclosure and upon further movement is locked into a position which maintains the valve fully open.
In another form of the invention, the locking means includes a release tab having a catch adapted to engage a tab on the actuator to hold the valve open. The release tab is mounted on an arm which is movable between a first position in which the catch engages the actuator tab so that the valve is locked open and a second position in which the catch is disengaged from the actuator tab so that the valve can close.
In a one embodiment of the invention the valve member is connected to the actuator, the arrangement being such that the actuator opens the valve by moving the valve member away from the valve seat and that the locking means is engaged only when the valve is fully open.